Electrical service providers such as electrical utilities employ electricity meters to monitor energy consumption by customers (or other entities). Electricity meters track the amount of energy consumed by a load (e.g. the customer), typically measured in kilowatt-hours (“kwh”), at each customer's facility. The service provider uses the consumption information primarily for billing, but also for resource allocation planning and other purposes.
Many current electricity meters use digital circuitry to determine energy consumption and other billing values. For example, it is known to digital signal processors to calculate energy consumption from digital energy measurement signals. The calculated consumption information is then displayed on a meter display. From time to time, a meter reader from the utility obtains the consumption information displayed on the customer's meter display, thereby enabling billing. In the alternative, or in addition, the meter may include transmission capabilities for transmitting consumption information to a remote utility computing device, thereby also enabling billing.
Electrical power is transmitted and delivered to load in many forms. For example, electrical power may be delivered as polyphase wye-connected or delta-connected power or as single phase power. Such various forms are known as service types. Different standard electricity meter types, known as meter forms, are used to measure the power consumption for the various service types. The commonly used meter forms in the United States include those designated as 2S, 3S, 5S, 45S, 6S, 36S, 9S, 16S, 12S and 25S meter forms, which are well known in the art.
A primary purpose of metering is to allow a utility to obtain information regarding the energy usage by a load (customer) for the purposes of accurate billing and/or planning. To this end, meters employ multiple methods of communicating energy usage (and other) information. The methods of communication include displaying meter values at the meter location, communicating meter values in locally transmitted signals, and communicating meter values using remote communication methods. While communication of signals to local or remote computing devices is in widespread use, the most common means for communicating energy use is through the meter display.
In electronic meters, the meter display is often a relatively simple LCD segmented display panel that displays basic information, such as an accumulated energy usage value. In some meters, a technician can manipulate the display to obtain additional information about the meter.
One drawback to electronic meters with LCD (or other electronic) displays is that the display generally does not work during a power outages. To this end, in most electronic meters, the power for the meter circuits is obtained from the utility power lines that are being measured. When power is absent, the meter loses power. However, the utility meter has no energy consumption to measure when line power is absent, and the power loss to the meter is tolerable.
Nevertheless, it is sometimes desirable to access to information within a meter even when power is absent. For example, it is not inconceivable the periodic meter reading to take place during a power outage. In such a case, the lack of displayed information can be a disadvantage. Moreover, in many cases the power may be purposefully disconnected from a load for various reasons. In such cases, again, it may be a disadvantage to lack displayed information about a meter.
In most cases, the only way to obtain information from a meter during a power outage is to restart the meter, which requires utility power. This is not always possible, and in the case of purposefully removed power, disadvantageous.
Accordingly, there is a need for a method of obtaining data from a meter when utility power is absent from the meter.